Locomotive brake equipment



LDCQMOTIYE BRAKE EQUIPMENT Filed Feb. 16. 1927 r F n i 20 2 Sheets-Sheet1 INVENTOR UNCAS A.WH|TAY\E R awry WW ATTORNEY w a WWW 2 Sheets-Sheet 2r 83 I! I3 SERVICE. APPUCATION P GH ION INVENTOR UNCAS A.WHITAKERATTORNEY u. A. WHITAKER LOCOMOTIVE BRAKE EQUIPMENT F'iled Feb. 16. 192783 //3 RELEASE PosmoN v T195. 124 /20 I 3 9 Nov, 22, ;927. T

I EMERGENCY APPLICATION POSITION Patented Nov. 22, 1927.

UNCAS A. WHITAKER, or WILMEED'ING, PENNSYLVANIA, assreNou 1,650,310PATENT OFFICE.

TO THE WEST- INGHOUSE AIR BRAKE COMPANY, OF WILTlVIERDING, PENNSYLVANIA,CORPORA- TION OF PENNSYLVANIA.

LOCOMOTIVE BRAKE EQUIPMENT.

Application filed February 16, 1927; Serial No. 168,590.

This inventionrelates to fluid pressure brakes and more particularly .toa locomo tive brake equipment.

In the usual fluid pressure locomotive brake equipment, a distributingvalve device is employed having an application portion for controllingthe supply and release of fluid under pressure to and from the brakecylinder, and an equalizing. portion operated by variationsin brake pipepressure for I motive brake will tend to release,rwhen notcontrollingthe operation'ot the application portion.

W hen the equalizing portion is in lap position, after. effecting aservice application of the brakes, if leakage of fluid under pres sure,acting on the application piston of the application portion, shouldoccur, the loco,-

desired. f In graduating train, the brake pipe pressure is increasedgradually in the usual manner, to cause movement of the triple valvedevice to re lease position, and then the brake valve device is moved tolap position; On cars equipped ivith'meanstor graduating the re- "leaseof the brakes, the brake cylinder pressure is reduced to. a degreeproportional to the degree of increase in brake pipe pressure, but onthe locomotive, theequalizing portion of the distributing valve deviceis shifted to release position by the gradual" increase in brake pipepressure and 'remains there, so that the application cylinder 1sconnected through the equalizing slide valves to the usuakrelease pipeand thence to the at mosphere in the running position of the usualautomatic brake valve device. lVhen the brake valve device is moved tolap position, the release of fluid under pressure from the applicationcylinder and thence to the brake cylinder, is cut ott, so that the rateof release of fluid under pressure from the 10- comotive brake cylinderdoes notcorrespond with the rate of increase in the brake pipe pressure.and consequently will not correspond with the rate at which the brakesare released on cars equipped with means for graduating the release ofthe brakes.

One object of my invention is to provide an improved locomotive fluidpressure brake equipment, in which the pressure in'the' applicationcylinder will be maintained against the release of brakes onthe lapposition, after having made a service application of the brakes. V yAnother object of my invention. is "to provide an improved locomotivefluid pressure brake equipment in which graduated release of the brakeswill be effected at a rate corresponding with the rate of increase inbrake pipe pressure. v I

Other objects and advantages will appear in the following more detaileddescription of my invention. 7 e

In the accompanying drawings; Fig. 1 is a diagrammatic view, partlyin'secti'on, of a locomotive fluid pressure brake equipment embodying myinvention; Fig. 2 a sectional view of thedistributing valve deviceemployed in the construction shown in Fig. 1; Fig. 3 is a partialsectionof the automatic brake valve device,showing the rotary valve in releaseposition; Fig. 4 is a partial section of the automatic brake valvedevice,

showing the rotary valve in service application position; and Fig. 5isapartial section of the automatic brake valve device, showdependentbrake valve device 2, a distributing valve device 3,.a change-over valved'e- "vice 4, the usual feed valve device 5, a reducing valve device 6,a mainv reservoir 7, and a locomotive brake cylinder 8.

The automatic brake valve devlce 1 com prises; a casing having a chamber18, conv taining a rotary valve19, adapted to be operated by a handle20. j v

The distributingvalve device-3 comprises an equalizingportionQl and anapplication portion 22. The equalizing portion21comprises four diaphragmheads 23, 24,; 25, and 26, connected together by, astem- 39. The

chamber 27 at the outer face of diaph 'agm 23 is connected through apassage 28 with a control chamber 29, the volume of which is increasedby the addition of a chamber 29, which is connected to chamber 29through passage 62. The chamber 30, intermediate the diaphragms 23 and2t, is open to the atmosphere through a port 31. The chamber 32,intermediate thediaphragms 241 and 25, is in constant con'imunicationwith the usual application cylinder pipe 33. lhe chamber 341,intermediate the diaphragms and 26, is open to the atmosphere through aport 35, and chamber 36rat the outer face of diaphragm 26 is connectedto a volume cham 'ber 36 through a plurality of ports 37, the

chamber 36 being connected to the. brake pipe 16 through passage 94 andpipe 78. Movable with the stem 39 is a slide valve 38.

A coil'compression spring 40 is contained in chamber 36 and acts on theouter end 01 stem 39, and extending from the partition wall separatingthe chambers 36 and 36 is a stop 41 adapted to engage the end of thestem 39 and limit the movement thereof to the right. Normally, thespring 10 holds the stem 39 and the diaphragm heads in the left handposition, as shown in the drawings,

in which the opposite end out the stem 39 engages the centrally locatedstop lug t2.

The application portion 22 comprises a casing having a piston chamber .3containingan application piston at and a valve chamber 45 containing anexhaust slide valve 46, adapted to be operated by a stem 17 secured tothe piston a l. On the stem 47, intermediate the piston a l and slidevalve as, is a small piston 4L8 contained in chamber 19, and the chamberformed between said pistons is connected by passage to passage 51, whichleads to a pipe 52, connected to the brake cylinder 8. 7

Upon a predetermined inward movement of the application piston 44, thestem t? is acapted to engage and operate a poppet valve 53 contained inchamber The pop pet valve is acted uponby a spring 55, adaptedtonormally hold said valve seated against the seat ring 56.

The application piston chamber ifi is connected by a pipe lll to asafety valve 112,

adapted to limit the pressure build-up in said chamber.

' Contained in chamber 29 oi the distributingvalve'device, is a chargingvalve device which comprises a flexible bellows dia- --phragm 57, havingsecured thereto a adapted to operate slide valve 'The chamber withinsaid diaphragmis connected through-a pipe 61 with protection reservoir60, so that movement of the diaphragm is dependent upon the opposingpressures in chamber 29 and in "the chamber within the diaphragm.

Alsocontained in the casing of the dis to the equaliz ng-piston chamber15.

ea er tributing valve device is a piston chamber 63, containing anemergency piston 64, adapted to operate a slide valve 65, contained inthe valve chamber 66, and held in its normal position, as shown in thedrawings, by

valve has a cavity 73, adapted in one position ot' the valve to connectpipe Tel, from the protection reservoir 60, to pipe 77 through a passage'75 containing a choke plug 76. In another position of the valve 71, thecavity 73 connects pipe 78 and the brake pipe 16 to pipe 'Msleading tothe protection reservoir 60. V

In operation, fluid from the main reservoir 7 is supplied through pipe79'to the usual feed valve device 5, from which fiui'd at a reducedpressure is supplied through pipe 80 to the automatic brake valvedevice. With the brake valve in running position, assho n in Fig. 1,fluid at the reduced feed valve pressure then flows through pipe 80,paspressure is also supplied from passage 33 to the brake pipe 16 andthrough passage 88 The pressure being thus equalized on opposite sidesot the equalizing piston 12, the discharge valve 1'? is'held seated, asshown in the drawing.

Fluid at "teed valve pressure is supplied from passage 8 1 in theautomatic brake valve device to port 89 in the rotary valve 10, and

thence through passage 90, pipe 77, choke )lu Y6 in the chan e-over valvdevice atpassage 75, cavity in theplug valve171, and pipe 74k to theprotection reservoir60, and from pipe 74 through pipe 61 to the chamberwithin the bellows diaphragm 57. In initially charging the equipment,there being no fluid under pressure invalvechamher 29, the pressureof'ttuid within he bellows diaphragm 5i siiit'ts the" slide valve 59 tothe lett and uncovers the passage 91 connected to the pipe 61. Fluid atfeed valve pressure -'t'roni pipe 61 is thus permitted to I 'tlow'to thevalve chamber 29, the chamber 29 and through passage 28 tO Cl-IQ diaphragm chamber 2 V The protection r rvoir 60 is charged, abovedescribed, wmh fluid under pressure, to the adjustment of the feed valvedevice 5, and when the chambers 29 and 27 are charged to substantiallyfeed valve pressure, the balancing of pressures on the bellows diaphragm57 causes said diaphragm to collapse and shift the slide valve 59to theright, so as to lap the passage 91.

tion against the diaphragm stop 42, as shown in the drawings. Fluid atbrake pipe pressure frofh'passage 94 also flows into the emergencypiston chamber 63. The pressures being equal on opposite sides of saidoiston the aressure of the sorin 67 holds l 7 l i c:

the piston and slide valve in the position shown in the drawings.

Fluid at main reservoir pressure from pipe 79 is supplied through pipe95 and passages 90, 97, and 98 in the distributing valve device, topoppet valve chamber 54, and from passage 97 through cavity 99 in theequalizing slide valve 38 and passage 100. to the application reservoir101, charging the valve chamber 54 and the reservoir 101 with fluidunder pressure.

VVith-the automatic brake'valve devicel and independent brake valvedevice 2 in running position, the application piston chamber 43 ot thedistributing valve device is vented to the atmosphere through pipe 102,the application cylinder pipe 33, the

equalizing valve chamber 32, passage 103, the release pipe 104, cavity105 in the rotary valve 19 of the independent brake valve device 2, andthe atmospheric exhaust passage 106.

Vith the application cylinder 43 vented to the atmosphere, theapplication piston 44 and exhaust valve 46 will be held in the re leaseposition, as shown in the drawings, in which the brake cylinder 8 isconnected to the atmosphere through pipe 52, valve cham- V her-45 andthe exhaust passage 107.

The usual application cylinder pipe is connected to the rotary valveseat of both brake valve devices and is lapped in each, when in runningposition.

Fluid under pressure tronithe main reservoir 7 is supplied through. pipe108 to the usual reducing valve device 6, which operates to supply fluidat the reduced pressure usually employed for independent control of thelocomotive brakes, throughpipe 109 and port 110 in the rotaryvalve 19tothe rotary valve chamber 18 of the independent 'brakevalve device.

To effect a service application of the brakes, the automatic brake valvedevice is moved to service application position, as shown in Fig. 4,inwhich the passage 83 connected to the brake pipe16 is lapped by therotary valve, and fluid under pressure from the equalizing reservoir 14and the equalizing piston chamber 13 is vented to the atmosphere throughpassage 113, containing a restricted portion 114, cavity 115 in therotary valve 10 and to the atmosphere through the exhaust passage 116.When the desired reduction in the equalizing reservoir pressure has beeneffected, the brake valve device is moved to lap position, in

which no connections are made through the rotary valve '10,and theconnection of the equalizing reservoir 14 and equalizing piston chamber-13.to the atmosphere is thus lapped.

The reductionin pressure in the equalizing piston chamber 13 permits theopposing brake'pipe pressure in chamber 15 to shift the equalizingpiston 12 upwardly and thereby open the discharge valve 17 whichprermits the flow of fluid under pressure from chamber 15 and the brakepipe 16 to the atmosphere. hen the brake pipe pressure and the pressurein chamber 15 becomes reduced to a degree slightly less than theequalizing reservoir pressure in chamber 13, the equalizing piston 12 isshifted downwardly and closes the discharge valve 17 and prevents afurther reduction in the pressure of the brake pipe fluid.

Chambers 36" and 36 in the distributing valve device 2-being-connectedto the brake pipe l6-through passage 94, choke plug 93,

and pipe 78, the pressure of the fluid in "said chambers reduceswiththebrake pipe pressure.

The pressure of the fluid in the diaphragm chamber 27 and the controlchambers 29 and 29, remaining constant during a service application ofthe brakes on account of being bottled up, the diaphragm heads 23, 24,25,

and 26 are shifted to theright against the reduced pressure ofthebrakepipe fluid in the chamber 36 and against the pressure of the spring 40,to service position. The slide valve 38-is shifted by said diaphragn'iheads to service position, in which position passage 103, connected tothe usual release pipe 104,

is lapped, and passage 100 from'the application reservoir 101 isconnected to the chamber 32. Fluid under pressure from the ap plicationreservoir 101 then flows into chami361; 32 and through pipes 33 and 102to the application piston chainber 43, wherein said pressure acts on thepiston 44 and causes it to move to the right. The initial movementshifts the slide valve 46 and laps the atmosin which position fluid atmain reservoir pressure from chamber 5 1 is permitted to flow past thevalve to slide valve chamber 45, and thence through passage 51 and pipe52 to the locomotive brake cylinder 8, thereby applying the brakes.

Vi hen the pressure of fluid in the applieation' chamber 32 has beenincreased to a degree such that the increased pressure acting on thedifferential area of diphragm 24 with respect to diaphragm 25, issuliicient to overcome the eil'ect of reducing the brake pipe pressurein chamber 36, the diaphragm heads will be shifted to the left and theslide valve 38 thereby moved to lap position, in which the passage 100from the application reservoir is lapped, thereby preventing a furtherincrease of pressure in chambers 32 and 43. In lap position, the slidevalve 38 continues to cover the release pipe passage 103, so that fluidwill not be vented through said pipe in lap position.

Fluid at the pressure supplied to the brake cylinder also flows throughpassage 50 to the chamber between pistons it and 18, and when the brakecylinder pressure becomes silghtly greater than the pressure in theapplication cylinder 43, the application piston 44 is shifted to lapposition, in which position the poppet valve 58 is permitted to closeand prevent a further flow of fluid under pressure from the mainreservoir (0 the brake cylinder.

If a higher brake cylinder pressure is desired, a further reduction inbrake pipe pressure may be eifected, which will cause the equalizing andapplication portions of the distributing valve device to operate, in thesame manner as hereinbeiore described, to increase the brake cylinderpressure. Then the brake cylinder pressure can be applied in steps asdesired. 7

If, for any reason, the pressure in the diaphragm chamber 82 and in theapplication piston chamber 1-3 tends tobecome reduced, as by leakage, soas to tend to cause the application piston 44 and exhaust slide valve 46to be shifted to release position and thus cause a release of thebrakes, the equilibrium of fluid pressures on the diaphragm-heads inmove the slide valve 38 back to lap position.

The operation of the distributing valve device will thus maintain theapplication cylinder pressure, and consequently the brake cylinderpressure, up to the capacity of the application reservoir 101.

, reduced.

To release the locomotive brakes after a 7 service application of the.brakes, the brake valve device 1 may be returned to running position, inwhich the brake pipe pressure and the pressure in chambers 56 and of thedistributing valve device is increased. The increase in pressureinchamber destroys the equilibrium of the diaphragm heads and shirts saidheads, against the application cylinder pressure in diaphragm chamber 32and control reservoir pressure in diaphragm chamber 27, to releaseposition in which the stem 39 strikes the stop e2. The slide valve 38 isshifted to release position, as shown in the drawings, in which thefluid under pressure in the application cylinder a3 and diaphragmchamber 32 is vented to the atmosphere through passage 103 and thereleasepipe 10 i, as hereinbetore explained.

Venting ot' fluid under pressure trom the application piston chamber 43permits the higher brake cylinder pressure acting on the opposite sideof the application piston 4 1- to shift said piston and the slide valve16 to release position, in which fluid under pres sure is vented fromthe brake cylinder 8 through pipe 52, passage 51, valve chamber 45, andthe atmospheric exhaust passage 10?".

If it is desired to graduatethe release 01 the brakes, the fluid underpressure in the brake pipe is only partially restored, and the automaticbrake valve device 1 is then moved to lap position. The increase inbrake pipe pressure and pressure in chamber 36 of the distributing valvedevice operates,as above described, to shift the equalizing portion ofthe distributing valve device to release positlon, in which the pressurein the application cylinder L3 and the brake cylinder 8 is When theapplication cylinder pressure and the pressure in the diaphragm chamberbecome reduced to a degree corresponding with the increase in brake pipepressure, the forces acting on the diaphragm heads 23, 2st, 535, and 20,operate the heads to shift the slide valve 38 back to lap position, inwhich a further decrease'in application cylinder pressure is prevented.Then when the brake cylinder pressure becomes reduced to a degreeslightly less than the application cylinder pressure, acting in" chamber43, the application piston and slide valve are shifted back to lapposition, in which the atmos pheric exhaust pa sage 107 is lapped andprevents a further decrease in brake cylinder pressure.

The brake pipepressure may thus be re stored in steps as desired, andtherdistrib uting valve device will be operatedby the increased brakepipe pressure to permit a proportional and graduated release of fluidunder pressure from the locomotive brake cylinder.'

It is common practice, especially on long trains and where aquicl:release or the brakes is'desired, to initially move the auto matic brakevalve to release position, as

shown in Fig. 3, in which position fluid at main reservoir pressure fromchamber '9,

supplied thereto through pipe 117, from the )revent ovcrchar 'e of theauxiliar reser-V voirs on the cars at the head of the train. The brakevalve is then moved from release position to running position, in whichthe high head of pressure in the brake pipe at" the head of the trainreduces, by flow to the rear of the train, to the pressure at which thefeed valve device is adjusted, the feed valve then controlling theremainder of the brake pipe charging.

To prevent overcharging of the control chambers 29 and 29, when thebrake valve device is in release position, the pipe 61 and theprotection reservoir are connected to the atmosphere through pipe 7a,cavity 7 3 in the plug valve 71, passage 75, choke plug 7 6, pipe 77,passage 90 in the automatic brake valve device 1, cavity 119 in therotary valve 10 and the atmospheric exhaust passage 116. The pressure inthe protection reservoir is thus reduced, so that when the automaticbrake valve device is turned from release-to running position, theconnection of the brake pipe, with its momentary high head of pressure,to the protection reservoir through the controlling choke plug 7 6 inthe change-over valve device l, will not cause a build-up of pressure inthe protection reservoir higher than the adjustment of the feed valvedevice, before the high pressure head is reduced by equalizing to therear of thetrain. By preventing the protection reservoir from becomingovercharged, the pressure of thefluid in the control'chambers 29 and 29will never exceed the pressure due to the adjustment of the feed valvedevice 5, and furthermore prevents an undesired application of thelocomotive brakes, such as would occur if the pressure in the diaphragmcontrol chamber 27 should exceed the opposing full "brake pipe pressurein diaphragm chamber 36.

To effect an emergency application of the brakes, the automatic brakevalve device is moved to emergency position, as shown in Fig. 5, inwhich position the brake pipe 16 is suddenly vented directly to theatmosphere through passages 83 and 84, cavity 120 in the rotary valve 10and through the atniospheric exhaust passage 116, thereby initiating .aquick serial emergency action throughout the train, in the usual manner.

Choke 93 in the brake pipe passage 94 in the distributing valve deviceprevents a sudden cmcrgency reduction inthe pressure in chambers 36and36, but the brake pipe is connected through pipe 7 8 and passage 92 tothe emergency valve chamber 66. The pressure in said chamber is thussuddenly reduced with brake" pipe pressure, so that the higher pressurein piston chamber 63 is permitted to shift the piston 64 and slidevalve.

65 upward against the pressure of the spring 67 to a position in'Whichport 121 through the slide valve registers with passage 122 from thechamber 36 The fluid under pressure in chainbers36 and 36 is thussuddenly reduced by flow through the valve chamber 66,,passage 92 andpipe 78 to the brake pipe 16, and thence to the atmosphere.

The sudden reduction of the pressure in chamber 36 permits the controlchamber pressure in diaphragm chamber 27 to shift the diaphragm headsand slide valve'38 to emergency position against the stop 41, whichcorresponds with the service position.

' The fluid under pressure in the application reservoir 101 is thenpermitted to flow-to the application cylinder 43 and operate theapplication piston to apply the locomotive brakes in the same manner asin service.

The pressure developed in the application piston chamber 43 tends to behigh, due to the equalization of the fluid under pressure from theapplication reservoir into the application piston chamber 43, but toprevent an excessive pressure and consequently an excessive applicationof the brakes, the

application piston chamber. is connected through pipe 111 to a safetyvalve 112,v

which-graduallyblows down the pressure in the application chamber 43 andthus limits the application cylinder maximum degree.

In order to prevent an undesired release of the brakes in the emergencyapplication position, due to possible leakage of fluid underpressurefrom the application piston chamber to the atmosphere, the applicationcylinder. pipe 33, which is connected to the application piston chamberthrough pipe 102, registers with cavity '123-in the rotary valve 10 ofthe automatic brake valve device, which cavity is connected throughpassage 81 and av restricted port'12-it in the rotary valve 10 .to therotary valve chamber 9. Fluid at main reservoir pressure in chamber!) isthus permitted to flow to the application piston chamber 43 and maintainthe pressure therein at the degree as determined by the safety valvedevice 112.

To apply the locomotive brakes independposition, as shown in thedrawings, to appressure to a safev plication position (not shown), inwhich fiuid at reducing valve pressure in pipe 109 is permitted to flowto the application cylinder pipe 33 and through pipe 102 to theapplication piston chamber 48, and therein acts upon and operates theapplication piston 44c to apply the locomotive brakes, as hereinbeioredescribed. Pipe 33 is also connected with diaphragm chamber 32, and thepressure of the fluid supplied thereto exerts an additional thrust tothe left on the diaphragm heads, but this has no effect on theoperation; i

To release an application of the brakes, as effected by the independentbrake valve device, the independent brake valve device is moved torunning position, in which the application piston chamber 13 anddiaphragm chamber 32 are connected to the atmosphere through the releasepipe 104, or a quicker release or the application cylinder pressure maybe efiected by moving the independent brake valve device to releaseposition (not shown) and connecting the application cylinder pipe 33directly through a cavity in the rotary valve 19 to the atmosphericpassage 125.

By using release position of the independent brake valve device 2 tovent the application cylinder pipe 33 to the atmosphere, an applicationof the brakes previously made with the automatic brake valve device maybe released at any time, irrespective of the position of the automaticbrake valve device. When effecting such a release, the brake valveshould be held in release position long enough to permit the fiuid underpressure in the application reservoir 101 to e vented to the atmosphere,since the diaphragm heads would otherwise shift the slide valve 38 toservice position in an en deavor to maintain the application cylinderpressure.

Usually, the pressure in the brake pipe is maintained at the pressure atwhich the feed valve device is adjusted, but when op erating a traindown a grade, the brake valve device may be placed in full releaseposition, and the brake pipe pressure employed under suchcircumstancesis the pressure of the fluid. in the main reservoir.

Under such conditions, the change-over valve 4: is turned, so thatcavity 73 in the plug valve 71 connects pipe 78 from the brake pipe 16to pipe 7 1 connected to the protection reservoir 60, so that saidreservoir is charged directly from the brake pipe.

The reservoir is thus charged directly from the brake pipe instead of byway of ports in the automatic brake valve device, for the reason that,as hereinbefore described, in the release position of the brake valvedevice, the pipe 77 is connected through cavity 119 in the rotary valve10 with the exhaust port 116, and consequently,

when the brake valve device is maintained in release position, insteadof running position, the protection reservoir 60 would not be maintainedcharged with fluid under pressure.

If it is desired to cut out the graduated release feature, the plugvalve 68 in the distributing valve device 3 is turned, so that port 129connects passage to passage 69. Then, in graduating the release on thetam, when the diaphragm heads and slide valve 38 are shifted to releaseposition by an in-' crease in brake pipe pressure, effective in chamber36, cavity 127 in the slide valve 38 will connect the control chamber 29and diaphragn'i chamber 27 through passages 28 and 70, choke plug 126,port 129 in the plug valve 68 and passage 69 to passage 128 and chamber36, and consequently to the brake pipe 16. The fluid under pressure inthe diaphragm chamber 27 and control chamber 29 thus'equalize with thefluid under pressure in the brake pipe 16, so that even though the brakepipe is only partially recharged, there is no higher pressure ondiaphragm head 23 to shift the diaphragm heads and slide valve to lapposition, so as to cut oif the application cylinder connection to therelease pipe, and as a result a full and direct release of the brakeswill result.

The choke plug 126 is provided in passage 70 so'that when a. servicerate of reduction in the pressure in the diaphragm chamber 36 is made toapply the brakes, the back flow of fluid under pressure from diaphragmchamber 27 will be so restricted as to prevent a sufficient decrease inthe pressure in chamber 27 as to cause a failure to obtain a brakeapplication.

The choke plug 93 in passage 9% connecting chamber 36 to pipe 78 and thebrake pipe 16 is provided to cause a slight lag in the change inpressure in chamber 36 as compared to variations 1n pressure in thebrake pipe 16, so as to more nearly synchronize the operation of theequalizing portion of the distributing valve device with the valvedevices on they cars: in a train, and for this reason it is necessar toemploy the emergency piston 64 and slide valve 65, the operation ofwhich was described in connection with securing an emergency applicationof the brakes.

With the usual fluid pressure brake equipment, approximately a 4 poundreduction in auxiliary reservoir pressure is required to shift the brakecylinder piston from its release position to its app'lied position,while with a distributing valve device or" my improved construction,when the brake cylin-j der pressure is controlled directly by the brakepipe pressure, a 4 pound brake pipe reduction would tend to produceabout 15 pounds brake cylinder pressure. To make this distributing valvedevice operate sin1ul-' lit) taneously with the usual brake equipments,the spring 40 is provided, acting on the diaphragm head 26, and isadapted to prevent the initial 4 pounds reduction in brake pipe pressurefrom moving the diaphragm heads and slide valve 38 to service position.Further brake pipe reduction will, however, produce the same locomotivebrake cylinder pressure as obtained on the cars in the train.

If when effecting a service application of the brakes, the pressure inthe application piston chamber 43 should tend to build up undesirably,the safety valve 112 will prevent an excessive pressure from beingdeveloped.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder,

of means subject to the opposing pressures oi the brake pipe and achamber for controlling the fluid pressure in said chamber, and meanssubject to the opposing pressures of said chamber and the brake cylinderfor controlling the fluid pressure in the brake cylinder. 7 w

2. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder", of movab'le abutments subject to the opposing pressuresof the brake pipe and a chamber, valve means operated by said abutmentfor controlling the fluid pressure in said chamber, a movable abutmentsubject to the opposing pressures of the brake cylinder and saidchamber, and valve means operated by said abutment for controlling thefluid pressure in said brake cylinder.

3. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder, of movable abutments subject to the opposing pressuresof the brake pipe and a chamber, a reservoir normally charged with fluidunder pressure, valve means operated by said abutments upon a reductionin brake pipe pressure for supplying fluid from said reservoir to saidchamber, and means subject to the opposing pressures of the brakecylinder and said chamber for controlling the fluid pressure in thebrake cylinder.

4:. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder, of movable abutments subject to the pressures of thebrake pipe,-a first chamber, and a second chamber, means for maintainingthe pressure in the first chamber at a predetermined degree,independently of the brake pipe, valve means operated'by said abutmentsfor controlling the fluid pressure in the second chamber, and meanscontrolled by the pressure in the second chamber for controlling thepressure in the brake cylinder.

5. In a fluid pressure brake, the combination with a brake pipe andbrake cylinder, of movable abutments subject to the pressures of thebrake pipe, a first chamber, and

a second chamber, valve means operated by I said abutments forcontrolling the fluid pres sure in the second chamber, means controlledby the pressure in the second chamber for controlling the fluid pressurein the brake cylinder, a reservoir from which fluid is supplied to theflrstchamber, and a brake valve device having a running position inwhich fluid under pressure is supplied to the said reservoir, and arelease position, in which fluid is vented from said reservoir.

6. In a fluid pressure brake, the combination with a brake pipe, ofmeans subject to the opposing pressures of the brake pipe and a chamberfor controlling the brakes, a reservoir from which'fluid is supplied tosaid chamber, and a brake valve device having a running position inwhich fluid under pressure is supplied to said reservoir, and a releaseposition in which fluid is vented from said reservoir.

7. In a fluid pressure brake, the combination with a brake pipe, ofmeans subject to the opposing pressures of the brake pipeand a chamberfor controlling the brakes, a source offluid under pressure, a movableabutment subjectto the opposing pressures of said chamber-andsaidsource, and valve means operated by said abutment for con trollingthe supply of fluid from said source to said chamber.

8. In a fluid pressure brake, the combination with a brake pipe, ofmeans subject to the opposing pressures of the brake pipe and a chamberfor controlling the brakes, a source of fluid under pressure, a, movableabutment subject to the opposing pressures of said chamber and saidsource, and valve means operated by said abutment for controlling thesupply of fluid from said source to said chamber, communication fromsaid source to said chamber being closed upon equalization of fluidpressures on opposite sides of said abutment.

9. In a fluid pressure brake, the combination with a brake pipe, ofmeans subject to the opposing pressures of two chambers, one of which isopen to the brake pipe through a restricted port, for controlling thebrakes, and means operated upon a sudden reduction in brake pipepressure for connecting said brake pipe chamber to the brake pipethrough a larger port.

10. In a fluid pressure brake, the combination With a brake pipe, ofmeans subject to the opposing pressures of the brake pipe and a chamberfor controlling the brakes, a reservoir adapted to be charged with fluidunder pressure, and meanssubject to the opposing pressures of saidchamber and said reservoir for controlling communication from saidreservoir to said chamber.

11. In a fluid pressure brake, the-combination with a brake pipe,'ofmovable abutfill ments subject to the pressures of the brake pipe, 21first chamber, and a second chamber, valve means operated by saidabutments for controlling the fluid pressure in the second chamber,means for normally maintaining the pressure in the first chamber, andnormally operable means for controlling communication through whichfluid under pressure is supplied to said lirst chamber.

12. In fluid pressure brake, the combina tion with a brake pipe, oimeans subject to the opposing pressures of the brake pipe and a chamberfor controlling the brakes, a reservoir, a brake valve device having aposition for supplying fluid under pressure to said reservoir, and meanssubject to the op iosing pressures of said reservoir and said chamberfor controlling umrmunication from said reservoir to said chamber.

13. In a liuid pressure brake, the combination with a brake pipe, oi?means subject to the opposing pressures of the brake pipe and a chamberfor controlling the brakes, a reservoir from which fluid under pressureis supplied to said chamber, a brake valve device through which saidreservoir is normally charged with fluid under pressure, and valve meansoperable to connect said reservoir directly to the brake pipe.

14:. In a fluid pressure brake, the combination with a brake pipe, ofmeans subject to the opposing pressures oi the brake pipe and a chamberfor controlling the brakes, a

reservoir from which fluid under pressure is supplied to said chamber, abrake valve device through which said reservoir is normally charged withfluid under pressure, and valve means operable to connect said reservoirdirectly to the brake pipe, independently of said valve device. 7

15. In a fluid pressure brake, the combination with a brake pipe, ofmeans subject to the opposing pressures of the brake pipe and a chamberfor controlling the brakes, a reservoir from which fluid under pressureis supplied to said chamber, a brake valve device through which saidreservoir is normally charged with fluid under pressure, andmanually.operable valve means adapted in one position to establishcommunication through which fluid under pressure is supplied from thebrake valve device to said reservoir and in another position to connectthe brake pip-e directly to said reservoir.

In testimony whereof I have hereunto set my hand.

UNOAS A. WHITAKER.

